SOLUTION: Aidan is doing a multiple choice test with 20 questions. He scores 3 marks for a correct answer and loses one mark if the answer is incorrect. Aidan answers all questions and scor
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Question 512059: Aidan is doing a multiple choice test with 20 questions. He scores 3 marks for a correct answer and loses one mark if the answer is incorrect. Aidan answers all questions and scores 40 marks. How many has he got right? Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! Aidan is doing a multiple choice test with 20 questions. He scores 3 marks for a correct answer and loses one mark if the answer is incorrect. Aidan answers all questions and scores 40 marks. How many has he got right?
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Quantity Eq::: c + w = 20
Points Eq:::: 3c - w = 40
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Add and solve for "c":
4c = 60
c = 15 (# of correct answers)
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Solve for "w":
c +w = 20
15 + w = 20
w = 5 (# of wrong answers)
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Cheers,
Stan H.
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